[SOLVED] Build failure : undefined reference to `gluPerspective'

[Zikkee13]

Hello everbody,

I have a build error when I try to build my Qt project with QtCreator. "undefined reference to `gluPerspective'".
My .pro file is :

@SOURCES +=
main.cpp
monwidgetopengl.cpp
mafenetre.cpp

HEADERS +=
monwidgetopengl.h
mafenetre.h
QT+= opengl
QT+= widgets@

My mafenetre.cpp file (the error comes from this file):

@#include "mafenetre.h"
#include <GL/glu.h>

// ...

// ...
void MaFenetre::resizeGL(int width, int height)
{
//...
gluPerspective(45.0f, (GLfloat)width/(GLfloat)height, 0.1f, 100.0f);
//...

}@

I don't understand why I have this error when I try to build my project. I have included the <GL/glu.h>, link opengl lib to my project...

If someone has an idea...
Thanks!

[SGaist]

Hi,

You need to provide more information: What OS ? What compiler ? What Qt version ?

[Zikkee13]

Ubuntu 12.10 with Qt 5.0.1 on QtCreator and g++.

[SGaist]

IIRC gluPerspective comes from the glut (freeglut ?) library. Are you linking against the glut library ?

[Zikkee13]

I tried using gluPerspective with SDL a few weeks ago and it works with the #include <GL/glu.h>...

[john_god]

Why don't you try glFrustum() instead ?

[SGaist]

Including glu.h has nothing to do with linking the library. Did you check that your program is linked with glut ?

What version of OpenGL are you using ? IIRC gluPerspective has been removed since OpenGL 3.0.

You can also find an implementation called qgluPerspective in the Boxes example

[Zikkee13]

I know for the gluPerspective removal since OpenGL 3.x. It's the OpenGL's version I have but as I said glPerspective works with another project with the SDL Library (and same compiler, OpenGL 3.x...) ; that's weird I know... if the glPerspective has been removed...
I'm going to check if my QtCreator is linked with glut ASAP... but it's GLU, not GLUT, I think. If it was GLUT my function should be glutPerspective, no?

@john_god, what's the difference between this function and gluPerspective?

[SGaist]

It's GLUT (GLUT stands for OpenGL Utility Toolkit)

gluPerspective does some mathematic for you and then uses glFrustrum. Either search for the implementation on google, or grep qgluPerspective in your Qt 5 sources.

[john_god]

[quote author="Zikkee13" date="1365005409"]@john_god, what's the difference between this function and gluPerspective?[/quote]

I'm too lazy to check the specs right now but I think they are the same, the diference is that gluPerspective adds GLUT dependency to your project, glFrustum() is OpenGL native.
Go check it out on google :)

Edit: Ok I just check them, they are no the same, please check glOrtho(). Basically all this functions do is to setup diferent math perspectives / projections to your world.

[Zikkee13]

I have added GLU .so file (/usr/lib/i386-linux-gnu/libGLU.so) to my project and it works.
GLUT is not installed on my laptop and it works without it.

Thanks for your help. Solved.

Edit : @john_god, OK thanks!

[gaia]

Hello, I have same problem compiling a project in qt5,
@ undefined reference to gluPerspective@
@undefined reference to gluLookAt@

i'm on Debian Wheezy 64bit ..

[soleyla]

I had the same problem as gaia and solved it by adding

@LIBS += -lglut -lGLU@

to the .pro file of my project